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Three-dimensional surface images can be reconstructed from CT scans. These are particularly useful in the study and management of patients with congenital and acquired craniofacial deformities. The principles of 3-D reformation, the production of the surface images, and recent advances in modification of these images for specific clinical needs are presented.
A computerized method of quantification, graphic representation and classification of sleep-wakefulness data in the cat before and after pontine tegmental lesions has been presented. Electrophysiological signal features including average EEG amplitude, average EMG amplitude and PGO spike rate which are particularly important for the definition of sleep-wakefulness states have been quantified for each 1 min epoch in the day. The data were presented in a projected 3-dimensional data display, in which they formed clusters that are considered to be analogous to sleep-wakefulness states. A cluster analysis algorithm was employed for the automatic classification of these data, and this automatic classification was compared graphically and with contingency table analyses to traditional visual assessment of state from polygraphic records. Although there were systematic differences in the locations of state boundaries, total percent agreement between cluster analysis classification and traditional human classification was comparable to the percent agreement between any two human classifiers (about 90%). After pontine tegmental lesions involving both the gigantocellular and lateral tegmental fields, paradoxical sleep was eliminated, and the characteristics of slow wave sleep and wakefulness were altered. The elimination of the state of paradoxical sleep was evident in the computer display by the absence of the paradoxical sleep cluster, and alterations of the other states were indicated in the display by shifts in the positions of their respective clusters. Automatic classification of slow wave sleep and wakefulness after such lesions compared well with traditional classification, attesting to the validity of this approach.
Analysis of X-ray crystallographic data for cephalosporins and 1- oxacephalosporins shows that, although the 1-methyl-1H- tetrazol -5- ylthiomethyl side chain at position 3 of a bicyclic beta-lactam nucleus has certain conformational preferences, it also has considerable flexibility. Both the C4 = C3-C3'-S and C3-C3'-S-C5" torsional angles are frequently observed in the vicinity of +/- 90 degrees. The distance between the tetrazole ring carbon C5" and the 4-carboxyl carbon ranges from 4.07 to 5.65 A. Mean bond lengths and bond angles for the 3 and 4 side chains are tabulated.
Programs are presented to plot the gross three-dimensional structure of the DNA double helix with the base sequence as input information. The rules that determine the overall structure of the double helix are those that predict the dependence of local helix parameters (specifically, helix twist angle and relative basepair roll angle) on sequence. For this purpose, the user can select either the Calladine-Dickerson parameters or the Tung-Harvey parameters. These programs can be used as tools to investigate the variation of DNA tertiary structure with sequence, which may play an important role in the sequence-specific recognition of DNA by proteins.
Model building and energy minimization procedures have been used to determine a productive substrate binding mode in liver alcohol dehydrogenase for secondary alcohols. These docking results have been compared to some of the extensive amounts of kinetic data available for this enzyme. The indirect diamond lattice approach first suggested by Prelog (Prelog, V. (1964) Pure Appl. Chem. 9, 119-130) to describe the active site of an enzyme has been used to build a direct diamond lattice from the crystallographic model of the enzyme. This lattice was oriented and positioned into the active site using the productive binding mode of cyclohexanol derivatives obtained from model building. We then classified the positions as allowed, forbidden, or boundary depending on their distances to protein atoms. We found very good agreement between the classification of our direct diamond lattice points and those of the indirect lattice obtained by others from kinetic studies. Finally we have extended the lattice as an aid to predict the stereospecificity of the enzyme for molecules which cover other regions of the active site.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Most of the available methods for preparing professional slides to be used in oral presentations can be cumbersome, time-consuming, and expensive. Creating high-quality 35-mm slides may require the use of expensive medical illustrators and photographic equipment not available to all physicians. More recently, technology has emerged that permits professional in-office generation of quality slides using commercially available computer graphics software and film recorders. Such a system is simple to establish and maintain when compared with commercial slide production facilities. We will review the hardware requirements of such a system, as well as the advantages and disadvantages of several commercially available software packages. Using a personal computer-based slide-making system, any physician communicating with small or large groups of people can now produce professional-looking slides easily, rapidly, and inexpensively.
A conformational study of four 5-HT1A (serotonin) receptor ligands ((R-(-)-methiothepin, spiperone, (S)-(-)-propranolol, and buspirone) led to the definition of a pharmacophore and a three-dimensional map of the 5-HT1A antagonist recognition site. These models were used to design new compounds and successfully predict their potency, stereospecificity, and selectivity. For example, 8-[4-[(1,4-benzodioxan-2-ylmethyl)amino] butyl]-8-azaspiro[4.5]decane-7,9-dione (1, MDL 72832) has nanomolar affinity (pIC50 = 9.14) for the 5-HT1A binding site in rat frontal cortex. As predicted, the S-(-) enantiomer of 1 was more active than its R-(+) enantiomer (pIC50 = 9.21 and 7.66, respectively) and a naphthalene analogue of 1 displayed the expected improved selectivity.
This paper describes the setting-up and management of a computer graphics service, mainly for producing 2 x 2 inch projection slides, by a department of medical illustration within a medical school. The service has been arranged to provide a limited facility for composing original illustrations by computer and to encourage medical and scientific staff to compose their own illustrations. These are recorded on magnetic disc for review and possible adjustment by medical illustrators. Images are then output as slides or paper prints by the medical illustration department. The range of equipment and apparatus used is described and evaluated briefly. Also described are the effects of the introduction of a computer-generated graphics service on the general work of non-patient slide production in the department.
A hypothetical model of the complex formed between the iron-sulfur protein rubredoxin and the tetraheme cytochrome c3 from the sulfate-reducing bacteria Desulfovibrio vulgaris (Hildenborough) has been proposed utilizing computer graphic modeling, computational methods and NMR spectroscopy. The proposed complex appears feasible on the basis of complementary electrostatic interaction and steric factors and is consistent with the data from NMR experiments. In this model, the non-heme iron atom of rubredoxin is in close proximity to heme 1 of cytochrome c3. The complex is stabilized by charge-pair interactions and hydrogen bonds. This complex is compared to the flavodoxin-cytochrome c3 complex previously proposed [Stewart, D. E., LeGall, J., Moura, I., Moura, J. J. G., Peck, H. D. Jr, Xavier, A. V., Weiner, P. K. & Wampler, J. E. (1988) Biochemistry 27, 2444-2450] and new NMR data shows that both proteins interact with the same heme group of the cytochrome as postulated.
With the rapid developments in microprocessors, the widespread availability of computers has brought about broad applications in the field of orthopaedics. The present technology enables large quantities of data to be logically processed in a very short span of time. This has led to the development of information management database systems where relevant medical information may be retrieved very quickly and effectively. The analytical power of the computer has also been utilised in expert systems to assist in clinical-decision making process. Computer graphics have revolutionised the visualisation of physical features of internal and external body parts, providing new and improved modalities of diagnosis. In some centres, surgical planning and rehearsals are already being carried out at the computer terminal with the use of animation and computer graphics. Computer technology has also played an active role in the field of prosthetics and rehabilitation. Intelligent robotic systems and microprocessor with functional neuromuscular stimulation have been applied to benefit, and in some cases restore some motor functions to the physically disabled. With more collaboration between engineers, scientists and the medical community, several prototypes of computer-controlled prostheses and prosthesis designed and manufactured by Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) technology are available today to assist the amputees in their daily living and ambulatory activities.
This paper discusses the application of the data handling-graphics-statistics program Stata (Computing Resources Center, Santa Monica, CA) to radioimmunoassay. We have found that this program is more powerful and easier to use than a spreadsheet for analyzing various kinds of laboratory data generated from chromatography, radiolabeling experiments, enzyme-linked immunosorbent assays, and radioimmunoassays, to name several examples. Data from a radioimmunoassay procedure, originally analyzed using a spreadsheet, Lotus 1-2-3, have been processed with Stata. Simple programs (batch files) have been devised for computations and graphics. The original data and a comparison of results are presented.
Interactive computer-graphics methods of computer-aided design (CAD) have been applied to problems in physical science and industry for several years; however, at the present time CAD methods have not been widely used to solve similar problems in medical education. Electrocardiogram waveform fabrication for the production of teaching materials seemed to be a well-defined area for CAD application. The availability of inexpensive, 16/32 bit word, MC68000-based microcomputers (e.g. Apple, Macintosh) and interactive graphics software (e.g. MacPaint and MacDraw) seemed to provide the necessary tools to make this application. This paper describes the authors' initial experience (from June 1984 to March 1985) in developing and employing an interactive computer graphics routine to produce ECG teaching materials.
A descriptive medium for the presentation of protein structure has been developed and used to evaluate the structure of the active site of bovine trypsin (EC 3.4.21.4). This technique, involving advanced computer graphics technology, permits the facile display of a representation of the molecular surface of proteins of known structure and employs color to code the structural or chemical features of this surface. Benzamidine derivatives were inserted into the benzamidine-binding site of trypsin and the binary inhibitor-trypsin complex was evaluated by using the computer-generated structure. On the basis of qualitative assessments of the contribution of electrostatic and hydrophobic forces to the binding energy associated with complex formation, we made predictions concerning the effects of interaction of benzamidine substituents and amino acid side chains upon the binding energy associated with inhibitor-protein binding. The computer display of the molecular surfaces of the binary complex of substituted benzamidines and trypsin permitted unique insight into the identity and chemical properties of the atoms that participate at the interface of the molecular surfaces of the inhibitor and the protein. The computer-generated molecular surface display can potentially be combined with quantitative definition of the physical forces involved in the interaction of molecular surfaces. This technology should facilitate the study of the structure-activity relationship of substrates, inhibitors, and drugs that bind to proteins of known three-dimensional structure.